Cell sorting is a technique whereby cells are separated based on their properties. Typically, in a first stage, cells propagate through a fluidic channel and are characterized, for example based on size. In a second stage, based on the characterization of each cell, each cell is sorted by deflecting that cell towards an outlet of the fluidic channel.
In alternate devices the deflection of cells is performed by generating a microbubble which creates a jet flow in the fluidic channel. The magnitude of the force of the jet flow on a cell determines to which outlet of the fluidic channel the cell is deflected.
A first problem in these alternate devices is the time to generate a microbubble. Because cell sorting applications include high throughput, it is essential that microbubbles can be generated in a short span of time to keep up with the velocity of cells propagating through the fluidic channel.
A second problem relates to the temperature used to create microbubbles. To bring a liquid to its boiling point on a micro scale, a higher temperature is used than the boiling temperature of bulk liquid. This phenomenon is known as superheating. The use of higher temperatures leads to higher energy consumption and, related to the first problem, to a longer duration of the heating to create microbubbles.
A third problem relates to the accuracy of the sorting. The accuracy is related to the controllability of the generated microbubbles. In order to increase the accuracy, total control over the force created by the jet flow can be used. In alternate devices, this is lacking.
There is an opportunity for a micro-fluidic device which solves at least some of the problems stated above.